The present invention generally relates to imaging devices and, more particularly, to a system and method for calibration of imaging devices during the imaging process, and imaging devices utilizing the system and method.
Imaging devices capable of printing color images upon paper and other media are becoming increasing popular and used in many applications for color reproduction of images. For example, laser printers, ink jet printers, and digital printing presses are but a few examples of imaging devices in wide use today. As used herein, the term “imaging device” generally refers to all types of devices used for creating a printed image upon media.
As the use of color imaging devices continues to increase, the demand for quality color image reproduction has also increased for at least some imaging applications. For example, it is desirable in some color imaging applications to consistently generate color images of acceptable color consistency which may be considered to be one of the most important print quality characteristics. The demands may require spatial color consistency wherein colors are reproduced substantially the same over a given sheet of media. In addition, for applications where relatively high volumes of an image are generated, constant color consistency over time for many sheets of media may be desirable or of paramount importance. It may also be desirable or important to generate color images which match or are substantially the same as the images provided by a monitor, scanner, camera, other imaging devices, or otherwise provided for reproduction.
In one imaging example, a plurality of versions of the same image may be replicated on a single sheet of paper which is also reproduced in relatively high volumes by the same or different imaging devices (e.g., printing business cards). It is desirable to provide color consistency between the images on the same sheet of paper, as well as with respect to images on other sheets of paper from the same imaging device, and with respect to images from different imaging devices. Color consistency is dependent upon numerous physical parameters, such as consumables (photoconductor, marking agents, media, etc.), temperature, humidity, pressures, etc.
Color consistency is maintained in different manners. In some systems, predetermined color patches are periodically printed by the imaging device and inspected for color accuracy. The imaging device is then calibrated to correct any detected errors in color accuracy. However, such practices are often insufficient to provide the desired or required level of color consistency. In particular, color patch calibration is typically conducted infrequently due to consumable waste caused by the calibration, and due to the interruption of the workflow. Even if calibration is conducted between each job run, color drift within a job run is not corrected. Periodic calibration also fails to compensate for transient parameter variations that typically occur in the beginning of a job run (changing temperature, humidity, etc.), but which stabilize after a period of time. Also, it is often impractical to conduct a full color calibration every time a consumable (e.g., paper, ink, etc.) is changed.
The disclosure provides systems and methods which provide improvements with respect to color imaging, including improved color consistency.